some updates

single.go

@@ -0,0 +1,10 @@
+package filemanager
+
+import "net/http"
+
+// ServeSingleFile redirects the request for the respective method
+func (f FileManager) ServeSingleFile(w http.ResponseWriter, r *http.Request, file http.File, c *Config) (int, error) {
+	w.Header().Set("Content-Type", "text/plain")
+	w.Write([]byte("Hello"))
+	return 200, nil
+}